Europe's top human rights watchdog on Wednesday intensified its investigation into alleged secret CIA detention centres and covert flights, with Council of Europe chief Terry Davis urging European countries to provide full information on the issue.
Socialist lawmakers in the European Parliament urged the European Commission, the EU's head office, to launch its own inquiry.
"We cannot accept Guantanamo-like prisons in Europe," said Martine Roure, the Socialists' civil liberties coordinator. "We cannot accept that parts of Europe are not subject to the normal legal rules of detention and treatment ... The best way to fight the fanatics and terrorists is not to adopt their methods but rather to stress our values of fundamental human rights."
Bulgarian officials on Wednesday denied media reports that CIA aircraft allegedly landed at the Sarafovo airport near the Black Sea port of Burgas, and Portugal's Communist Party renewed its demand for the government to clarify similar reports.
US detention policies have come
in for worldwide criticism
Denmark said it would ask US authorities for details about the alleged transport of detainees on planes said to be used by the CIA over Danish territory.
The Pentagon will not disclose what countries the US military might fly over "or make brief refuelling stops in during detainee movements ... (because) doing so would constitute a safety risk to both the detainees and our troops," said a spokesman, Navy Lieutenant Commander Joe Carpenter.
In Austria, air force commander Major General Erich Wolf told state radio that the flight in question - a C-130 Hercules transport plane that took off from Frankfurt, Germany, and headed to Azerbaijan - crossed Austrian airspace on 21 January, 2003.
Austria's army scrambled fighter jets to make contact with the plane's pilot, but did not suspect anything wrong at the time and the government lodged no diplomatic protests, Wolf said.
Since then, Austrian authorities have found reason to believe the flight was transporting captives, Wolf added. He did not elaborate.
Peter Pilz, an official in charge of security issues for Austria's Green Party, criticised the military's handling of the incident, contending that sending up the jets and taking no further action amounted to providing an "honour escort" for the CIA plane.
Pilz accused the government and the Defence Ministry of "tolerating and playing down the illegal actions of the United States".
There have been no indications that any landings occurred in Austria, which refused to grant the United States permission to use its airspace during the US-led invasion of Iraq.
The flights have become an issue in many European countries amid reports that US intelligence may have transported suspected al-Qaida members and others en route to secret prisons in eastern Europe and other countries for interrogation.
Davis, speaking on Wednesday in Strasbourg, France, said he asked the governments of the Council of Europe's 45 member states how their laws ensure that acts by foreign agencies within their jurisdiction are subject to adequate controls.
On Tuesday, Swiss lawmaker Dick Marty - who is leading the inquiry - said he was investigating 31 suspect planes that landed in Europe in recent years, and was trying to acquire past satellite images of sites in Romania and Poland.
"We cannot accept Guantanamo-like prisons in Europe"
Socialists' civil liberties coordinator
Allegations that the CIA hid and interrogated key al-Qaida suspects at Soviet-era compounds in eastern Europe were first reported by The Washington Post on 2 November. The paper did not name the countries involved, but New York-based
Human Rights Watch said it had evidence indicating the CIA transported suspected terrorists captured in Afghanistan to Poland and Romania.
Other airports that might have been used by CIA aircraft in some capacity include Palma de Mallorca in Spain, Larnaca in Cyprus and Shannon in Ireland, as well as the US air base at Ramstein, Germany, Marty said.
Swedish authorities have confirmed one plane with alleged CIA links landed in Sweden three times since 2002.
Denmark says 14 flights with suspected CIA ties entered its airspace since 2001; Norway has confirmed three such flights.
Icelandic media have reported 67 landings, and there have been other unconfirmed reports in Macedonia and Malta.